Automated Custom Physical Design

Custom physical design is time consuming, prone to errors and boring.
However manual design is unsurpassed in terms of performance and
layout quality, and it is still widely used for library cells,
analog blocks, and to assemble mixed signal chips where crosstalk,
substrate noise and matching considerations must be taken into account.

In an automatic place & route environment the purpose of automation
is to complete a fully specified design with zero errors and with no
human intervention, often starting from scratch.
However in an interactive environment most of the work is incremental,
it is performed on an design where often some parts are missing during
part of the development, or are subject to frequent changes (ECOs).
The main purpose of automation therefore is to provide guidance to
the user, so that the design can be completed
manually as quickly as possible, and without errors.

Automating custom physical design is challenging. The freedom of the
designers cannot be constrained into predefined design styles. The speed
of the automation utilities embedded in an interactive environment often
must be comparable to the time between mouse clicks.
The ACPD methodology is based on the following main concepts: